While you think things through, you may be interested in taking a look at GasBag – an iPhone application that’ll let you drive your current ride to the gas station offering the cheapest fuel near you.

Jamcode’s application displays the prices of fuel at nearby petrol stations on a map on the iPhone and shows the way to a station. Information comes from other users who (hopefully) input the petrol price for stations.

The new software’s set for launch in Australia next month and has already attracted 75,000 US users. And there’s a hook to the tale that’s also quite interesting – the application is ads-funded, with Toyota, Kia, insurer Esurance and classifieds site Cars Direct sponsoring banner ads that appear alongside petrol price information on the iPhone.

The company in future hopes to add location-based ads for nearby local shops and other services through its application. Anyway, there’s a video clip after the break